Hydraulic shock absorber



ZABQQM Filed Sept. 15, 1945 2 a Ma r Z Z w I. 2 5 3. TM my INVENTOR fowl/Y F Ross/WAN H15 5 ATTORNEYS i a ten tec l Mar. 2

" FATE NT oer-1c E r v 23325901 'fifiz'iiitnifmcsnook-ABSORBER Ri isman, Daytn, Ohio, assignor to "General Motors Corporation, Detroit; Mich, a":

clearly shown.

In thedravvifist I V Fig. '1 i s'a fr ag ir'ieiita'iy;fictional-view 'of a shock absorberedflippedth the present invention. This section -'is-tja k n me 'fiirection 'and along the'line ofFi 'Fig. '2-'is-a't'i'ansverse section taken 'along' the 1ine-2 '2'-of V x Fig. 3 isa fiagmefifiarysctienai view of'a moan fied form of the Fig. 4 'is'a transverse s btiofial viw'takfi along the ine-4: 4p: Fig. 3. v

Fig. 5 is a view s ihii'lai td"Ffgf ii -shdwing 'another former-the invention, and

Fig. 6 is a ffragm'eritary, transverse section taken a16ngthe'1ine 6 6=-ofFig.5. I

Referring to the drawings-,theshockabsorber is shown comprising a? pair: of; concentric tubular members 20 and 21 bothseoured toan upper, h e m m e 2- Membe 01;-f9 *11 th i d of; the device and thesurrounciing tubular member 21 fo'rfns jthe fluid A rvoi'rz'il Within" the cylinder 2'!) vth'riefis mv deqpa reciprocative piston 24'hav'ing thelisual fli'fid flow'passage and valves not shown for establishing and controlling fluid new frbmbrie thep'ijston" to the other -'as"-it' isfrecip he ylin'der. A piston mi 25' hasone d seurd to "pistonz-i and s1idab1y eirtends ihroueh ai "packed bearing in the head member 22, having the anchoring member 26 secured-to its' erid whichextends to the exterior ofth'e head member. 'lhe'anchoring member '26 is secured to the'p1ate2l which is one of the two relatively movablej:members controlled by theshock-'=absoiber. --Rubbergrom- -mets 28 are interposedbetweemplate 21; the member26-and the'clainping -discfl.

'- At the bottom endiofi theficyliiiderlizi lit-there SIS 9.01am; (miles-'88).

provided ensure "orheau: member fenv having 'a central o ening 3' l 'siirrounde'd'= by an annular valve-"seajt 32 e x tending into tlzie:"cylincler2i]a A 'di'sc valve '33 is urged upon the valve-seat 1 32.5 by resilient" fingers" 34 -"forrned in a disc-ring :35 secured in the manner- 3a. Valve '33 has recesses 35 cut in its periphery to allow' the free passage close proXimity to the inner-wa11 of the head member for guiding purposes.

'Ihe closure mere-beast has a plurality of openin'gs 31 arrange ina circular row aroun'd-the valve-seat 32, esilient-ring;disc valve 38ihas its "inner annulareql 'ge secured to the :closure member 3D so as to flex saiti disc-valve and urge its outer portion against the-annular shoulder 39 formed on the-closure-member. -Normally' this Valve 38 -shuts on "communication r between the passagesoro'penings 31 and the I fluid:- reservoir jA- cap 41 has anannular recessin w hich the tubular 'memb'e 2 lis se'ated to secure it to said cap. Lugs i-n sa'id"cap provide a 'se'at for -the 'e'rid'head member 30"=W-hi1e providing a space under said member communication with the fluid reservoir 23. fiAny suitableanchoring: extension 43 is 5 provided on cap 4 l', by means of which this end of the 'shobk absorber may be attached totfie -other relatively movable members whose movement's are to be controlled by the shock absorber.

The pist0n'24 isof the standard design having fluid passages providing' for the transfer of "fluid from one side' of the"pi'ston to 'the Otherin response'to reciprocation thereof. Any'type-of standard fluid flowcontroivalvesare associated particular velvemeehams'm is shown in the draw =ings.- 7 The present shock' ab'sdrber isiparticularly "designed to control the movements-bf theframe and axles of 'a vhicl'e. when'so'us'ed; 'the piston-rod 25 isattached'to theframe of the' v'ehicle' represented by the number 21. -leer 2| "-fOrmingf tHefluid' 'resrvoinzt, and -its Thetubular memc ap 4| and anchorageHaresecured to'the vehicle axle. When the vehicle is-operated 'over a "roadbed the tvheels"on the axle, striking irregularities in theroadbed; will' cause the fluid containing tube 2 l '-to:be* shaken vigorouslymu'cmin "thecmanner.iofraccocktaih-shaker whennnsuse.

cause an upward surge of the fluid in the reservoir. Rapid repetitions of these movements will cause agitation of the fluid in the reservoir and a resulting aeration thereof.

To have substantially instant shock absorbe control it is necessary to have substantially solid or airfree fluid in the cylinder. If air-charged fluid is introduced into the working chamber I of the cylinder, the piston, on its stroke toward the end head member 3|] will first compress the air in the fluid thereby causing a lag in the proper valve 38 to the flow of fluid from the working chamber I00 into the reservoir 23 in response to movement of the piston 24 toward member 30. Thus valve 53 does not enter into the control of fluid flow to vary the resistance ofiered by the shock absorber.

Figs. 3 and 4 and Figs. 5 and 6 show modified forms of fluid movement control devices in the fluid reservoir which function to provide the same results as does the device of Figs. 1 and 2.

1 'In Figs. 3 and 4, the bafile I50 is secured beresistance to movement offered by the shock ab sorber. A substantially air-free fluid in the working chamber presents an uncompressible medium for resisting immediately the compression movement of the piston and thereby eliminating the lag mentioned.

To reduce fluid agitation and thereby minimize fluid aeration, the present invention provides a fluid movement controlling means in the reservoir which tends to hold the substantially solid or alrfree fluid in the reservoir, in the vicinity of the cylinder intake valve 33. Several forms of the invention are shown in the drawings. Referring particularly to Figs. 1 and 2, the means for con trolling the movement of fluid in the reservoir comprises a partition or baflle 50 in the form of a ring which is secured between the concentric tubes 20 and 2| at or below the minimum level of the fluid in the reservoir. The baflle 50 has a plurality of openings 5| providing for the transfer of fluid from one side of the battle to the other. Other holes are provided in the baflle, said holes receiving rivets or studs 52 which loosely support the ring-shaped disc valve 53, normally in spaced relation with the baille. Valve 53 has a plurality of slits 54 so spaced as to coincide with the openings 5| in the baille. These slits reduce the fluid flow capacity of the openings 5| in one direction so that when fluid movement upwardly causes the valve 53 to be moved on standards 52 to engage the partition or ,baiiie 50, this upward movement of the fluid from the lower side of the bafile to the upper will be substantially restricted. Thus, when the tube 2| is suddenly thrust upwardly, the resultant downward movement of the fluid in the reservoir will cause the valve 53 to be moved into its normal position as shown in Fig. 1, thereby permitting substantially unrestricted passage of the fluid through the openings 5| of the baflle. As a result, the comparatively air-free or solid fluid is urged toward the bottom of the reservoir and into the vicinity of the cylinder intake valve 33. On the other hand, when the tube 2| is suddenly thrust downwardly, the upward surge of the fluid, in consequence thereto, will move valve 53 up against the baflle 55 thereby reducing the openings 5| from full capacity flow to the flow capacity of the slits 54 in valve 53. -Thisrestricts the upward movement of the fluid through the baflle 55 and into the area of fluid agitation where air is mixed with the fluid. The restriction to fluid movement offered by the slits in valve '53- is substantially less than the restriction ofiered by tween tubes 20 and 2|.

It has a series of openings |5| providing for the substantially unrestricted flow of fluid from one side of the baflle to the other. .A flexible, ring-shaped disc valve I52 has its outer peripheral edge secured to the a partition or,baffle.|5 0. so that normally the valve flatly rests against the baffle as shown in Fig. 3. The inner peripheral edge of valve I52 has a series of semi-circular notches |54 equal in number' and similarly spacedas openings |5| so that normally a space I55 is provided at each openingwhich restricts the flow of fluid through said openings in one direction.

Figs. 5 and 6 show the baflle in the form of a frustoconically shaped member 250 made of any suitable thin flexible material. The hub portion of the baffle is secured to the cylinder 20 by a ring 252 while the outer peripheral edge engages the interior wall of the tube 2|. Slits 25| divide the baille into flexible segmental portions and also provide fluid restricting passages which restrict the flow or movement of fluid from the under to the upper side of the baflle. Downward movement of the fluid urges theouter edges of the segments awayfrom the tube 2| to provide for a substantially free flow of fluid from the top side to the lower side of the baille.

From the aforegoing it may clearly be seen that the present invention provides a fluid dampening baffle partition inthe reservoi at or beneath the level of the fluid therein, said partition having means operative to allow the fluid to pass downwardly through or around the baflle partition substantially freely in response to sudden upward thrusts of the shock absorber. However, passing of the fluid through or around the baille partition in the opposite direction in response to sudden downward thrusts of the shock absorber is substantially restricted so that the fluid is substantially prevented from passing freely from the reservoir section adjacent the intake valve to the cylinder into the upper portion of the reservoir where the presence of air tends to aeration of the fluid resulting from the violent shaking of the shock absorber during operation of the vehicle to which it is attached. This assures the presence of substantially air-free fluid in the working hamber of the cylinder and thus immediate control and resistance by the shock absorber.

While the embodiment of the present invention as herein disclosed, constitutes a preferred form, it is to be understood that other forms might be adopted,all'coming within the scope of the claims which follow.

What is claimed is as follows:

1'. An hydraulic shock'absorber comprising a cylinder; a piston in'said cylinder; a fluid reservoir surrounding and in communication with said cylinder; fluid'flow' controlling means between the cylinder 'and reservoir; and means fixed in the reservoir, below the minimum fluid l'evel therein, foriirest'ricting the movement of fluid in the reservoir to a greater degree in one direction than in the other.

2. An hydraulic shock absorber comprising a cylinder;.,a piston in said cylinder; a reservoir; an end member for the cylinder, said end memher having openings connecting the cylinder with the fluid reservoir; valves for controlling the fluid flow through said opening; and means fixed in the reservoir for restricting the movement of fluid in the reservoir away from said end member to a greater degree than the fluid movement toward said end member.

3. An hydraulic shock absorber comprising, a cylinder; a piston in said cylinder; a fluid reservoir; a cylinder end head having a plurality of passages connecting the cylinder with the reservoir; a valve for one of said passages providing for a substantially unrestricted flow of fluid from the reservoir into the cylinder; a valve for the other of said passages, providing for a restricted flow of fluid from the cylinder into the reservoir; and

' 6 fluid movement controlling means fixed in the reservoir, for restricting the movement of fluid in the reservoir away from said valves to a greater degree than the movement of the fluid in the reservoir toward said valves.

EDWIN F. ROSSMAN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS 

